During setup, the auto-join step has three switches:
All meetings on my calendar. Reunia can join every meeting it finds.
Only external meetings. Reunia joins meetings with people outside your organization.
Only meetings I host. Reunia joins meetings where you are the host.
Turn a switch off to leave that group out. The bot still needs a Zoom, Google Meet, or Microsoft Teams meeting. For a one-off call, paste the link from New Meeting → Add to live meeting.